Certified Medical Assistant (CMA AAMA)Safety and Infection ControlHard

A medical assistant is tasked with sterilizing heat-sensitive instruments that cannot withstand the high temperatures of an autoclave. Which of the following sterilization methods would be most appropriate for these instruments?

  1. ASteam sterilization (autoclave)
  2. BBoiling water for 30 minutes
  3. CEthylene oxide (gas) sterilization
  4. DDry heat sterilization
Show answer & explanation

Correct answer: C. Ethylene oxide (gas) sterilization

Ethylene oxide (EO) gas sterilization is a low-temperature method suitable for heat-sensitive instruments. Autoclaving and dry heat use high temperatures, and boiling water is disinfection, not sterilization.

Why the other options are wrong

  • A. Steam sterilization (autoclave) uses high heat and pressure, making it unsuitable for heat-sensitive instruments.
  • B. Boiling water is a method of high-level disinfection, not sterilization, as it may not kill all spores.
  • D. Dry heat sterilization also uses high temperatures, typically higher than steam, and is not suitable for heat-sensitive items.

Sterilization for Heat-Sensitive Instruments

For instruments that cannot withstand high temperatures, ethylene oxide (EO) gas sterilization is an appropriate low-temperature chemical method to achieve sterility.

  • Used for heat-sensitive items.
  • Chemical sterilization method.
  • Requires specialized equipment and aeration.

Memory trick: Heat-Sensitive? EO is the Easy Option.

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